Cis-3-hexenal-cis-3-hexenyl acetal compound, process for preparing same, and fragrance-or flavor-imparting or fragrance-or flavor-retaining agent and perfume composition containing same

ABSTRACT

A compound represented by formula (1): ##STR1## wherein R is alkyl or other hydrocarbyl, and a fragrance/flavor-imparting agent, a fragrance/flavor-retaining agent, and a perfume composition, each containing this compound as an active ingredient; and a process for preparing this compound either by reacting a compound of formula (2): ##STR2## wherein R 1  and R 2  are hydrocarbyl, with cis-3-hexen-1-ol, or by reacting cis-3-hexenal-di-cis-3-hexenyl acetal with an alcohol, R 7  OH.

TECHNICAL FIELD

This invention relates to a cis-3-hexenal-cis-3-hexenyl acetal compound,a process for producing the same, a fragrance- or flavor-imparting orfragrance- or flavor-retaining agent containing the same, and a perfumecomposition containing the same.

BACKGROUND ART

Fragrance- or flavor-imparting agents and fragrance- or flavor-retainingagents are widely used in the fields including beverages andcomestibles, cosmetics, sanitary and hygienic goods, detergents, bathrefreshing additives, and medicines and agricultural chemicals.Fragrance- or flavor-imparting agents are used for imparting fragranceor flavor. Fragrance- or flavor-retaining agents are used for enhancingor modifying, or retaining pleasant odor of a perfume or sweet taste ofa flavoring agent. Fragrance-imparting agents and flavor-impartingagents are referred to as "fragrance/flavor-imparting agents", andfragrance-retaining agents and flavor-retaining agents are referred toas "fragrance/flavor-imparting agents" in this specification.

Fragrance/flavor-imparting agents include numerous kinds offragrance-imparting agents and flavor-imparting agents. As examples offragrance/flavor-retaining agents, there can be mentioned solvents suchas benzyl benzoate, dialkyl phthalates, Hercolyn, limonene dimer,alkylene glycols, polyalkylene glycols, alkyl citrates and dialkyladipates; perfumes such as myrrh, Peru balsam, Tolu balsam, musks,civet, vanillin, hydroxycitronellal, olibanum, vetivert, benzylisoeugenol, ambrette, benzoin, labdanum, clary sage, cinnamic alcohol,orris, styrax, costus, coumarin, methyl naphthyl ketone, cinnamylcinnamate, ethyl cinnamate, 2-ethoxynaphthalene, naphthol ether,ambergris, rose phenone, oak moss, dimethyl hydroquinone, elemi, masticindole, patchouli basil, musk ketone and diphenyl methane; and zeolite,starch, talc, plastics, clays and cellulose. A suitablefragrance/flavor-retaining agent is chosen from thesefragrance/flavor-retaining agents depending upon the particular usethereof.

In recent years, green note fragrance/flavor-imparting agents includingcis-3-hexenyl alcohol (leaf alcohol) are widely used, and analoguesthereof such as esters are now being developed. As an example of suchanalogues, synthesis of cis-3-hexenal-di-cis-3-hexenyl acetal has beenreported in S. Arctander, "Perfume and Flavor Chemicals", Steffen,Arctander's Publications, Las Vegas, Nev. 1969. In this publication, itis reported that this compound has a low purity and its nature isextremely unstable, and thus, the compound would be of no practical useas a fragrance/flavor-imparting agent.

The present inventors have conducted researches into compounds of thetype described in the above publication, and found that, when thecompounds are highly purified, the compounds exhibit pleasant and strongfragrance and flavor, and are stable to a sufficient extent for the useas a fragrance/flavor-imparting agent.

DISCLOSURE OF INVENTION

An object of the present invention is to provide a novelcis-3-hexenal-cis-3-hexenyl acetal compound having favorablecharacteristics as a fragrance/flavor-imparting agent and/or afragrance/flavor-retaining agent.

Another object of the present invention is to provide a process forindustrially advantageously producing the novelcis-3-hexenal-cis-3-hexenyl acetal compound.

Still another object of the present invention is to provide afragrance/flavor-imparting or fragrance/flavor-retaining agentcomprising as an active ingredient a cis-3-hexenal-cis-3-hexenyl acetalcompound.

In one aspect of the present invention, there is provided acis-3-hexenal-cis-3-hexenyl acetal compound represented by the followingformula (1): ##STR3## wherein R represents an alkyl group having 1 to 20carbon atoms, which may have a substituent.

In another aspect of the present invention, there is provided a processfor preparing a cis-3-hexenal-cis-3-hexenyl acetal compound representedby the following formula (3): ##STR4## wherein R³ represents ahydrocarbon group which may have a substituent, which comprisesconducting an acetal exchange reaction in the presence of an acidcatalyst between an acetal compound represented by the following formula(2): ##STR5## wherein R¹ and R² independently represent a hydrocarbongroup except for a 3-hexenyl group, which may have a substituent, andcis-3-hexen-1-ol.

In still another aspect of the present invention, there is provided aprocess for preparing a cis-3-hexenal-cis-3-hexenyl acetal compoundrepresented by the following formula (6): ##STR6## wherein R¹ is ahydrocarbon group, except for 3-hexenyl group, which may have asubstituent, which comprises conducting an acetal exchanging reaction inthe presence of an acid catalyst between cis-3-hexenal-di-cis-hexenylacetal represented by the following formula (4): ##STR7## and an alcoholrepresented by the following formula (5):

    R.sup.1 OH                                                 (5)

wherein R¹ is the same as defined above for formula (6).

In a further aspect of the present invention, there is provided afragrance- or flavor-imparting or fragrance- or flavor-retaining agentcomprising as an active ingredient a cis-3-hexenal-cis-3-hexenyl acetalcompound represented by the above formula (3).

In a further aspect of the present invention, there is provided aperfume composition comprising as an active ingredient acis-3-hexenal-cis-3-hexenyl acetal compound represented by the aboveformula (3).

BEST MODE FOR CARRYING OUT THE INVENTION

The cis-3-hexenal-cis-3-hexenyl acetal compound of formula (1) is notdescribed in any publication and is a novel compound.

The cis-3-hexenal-cis-3-hexenyl acetal compound of formula (6) also is anovel compound.

In the novel acetal compound of formula (1), R in the formula is analkyl group having 1 to 20 carbon atoms which may have a substituent.

As specific examples of the alkyl group R, there can be mentionedstraight chain alkyl groups such as methyl, ethyl, n-propyl, n-butyl,n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl,n-dodecyl, n-tetradecyl, n-pentadecyl, n-hexadecyl, n-octadecyl andn-eicosyl, and branched alkyl groups such as isopropyl, isobutyl,sec-butyl, t-butyl, isopentyl, 2-methylbutyl, 1-methylbutyl, isohexyl,3-methylpentyl, 2-methylpentyl, 1-methylpentyl, isoheptyl, isooctyl and2-ethylhexyl. These alkyl groups may have a substituent, which does notexert baneful influence upon the synthesis reaction (acetal exchangereaction) for the compound of formula (1), such as an alkoxy group and ahalogen group. Of these alkyl groups, an alkyl group having 1 to 10carbon atoms and having 1 to 6 carbon atoms and having no substituent ismore preferable.

In the acetal compound of formula (3), R³ in the formula represents ahydrocarbon group preferably having 1 to 20 carbon atoms, which may havea substituent. As specific examples of the hydrocarbon group R³, therecan be mentioned alkyl groups which are listed above as regards R informula (1); alkenyl groups such as allyl, 2-butenyl, 3-butenyl,isobutenyl, 4-pentenyl, 3-pentenyl, trans-2-pentenyl, cis-2-pentenyl,1pentenyl, 3-methyl-2-pentenyl, 5-hexenyl, 2-hexenyl, trans-3-hexenyl,cis-3-hexenyl, heptenyl, octenyl, nonenyl, decenyl, dodecenyl,tetra-decenyl, octadecenyl and eicosenyl; and alkynyl groups such as2-butynyl, 3-butynyl, 4-pentynyl, 3-pentynyl, 2-pentynyl, 5-hexynyl,3-hexenyl, heptynyl, octynyl, decynyl, dodecynyl, octadecynyl andeicosynyl. These alkenyl groups and alkynyl groups may have asubstituent, which does not exert baneful influence upon the synthesisreaction (acetal exchange reaction) for the compound of formula (3),such as an alkoxy group and a halogen group. Of these hydrocarbongroups, an alkyl group having 1 to 15 carbon atoms and having nosubstituent, an alkenyl group having 2 to 15 carbon atoms and having nosubstituent, and an alkynyl group having 2 to 15 carbon atoms and havingno substituent are preferable. An alkyl group having 1 to 8 carbon atomsand having no substituent, and an alkenyl group having 2 to 8 carbonatoms and having no substituent are more preferable.

In the acetal compound of formula (6), R¹ in the formula represents ahydrocarbon group including those which are listed as regards R³ informula (3), except for 3-hexenyl group.

The acetal compounds represented by the formulae (1) and (3) areprepared by a process wherein the acetal compound of formula (2) andcis-3-hexen-1-ol are subjected to an acetal exchange reaction in thepresence of an acid catalyst, or a process wherein the acetal compoundof formula (4) and an alcohol R¹ OH are subjected to an acetal exchangereaction in the presence of an acid catalyst.

In the acetal compound of formula (2) and the alcohol of formula (5),which are used as starting materials, R¹ in these formulae is as definedabove as regards R¹ in formula (6), and R² is a hydrocarbon group whichmay have a substituent, and includes alkyl, alkenyl (except for3-hexenyl) and alkynyl groups, which are listed as regards R¹ in formula(6).

The acid catalyst used in the above-mentioned two acetal exchangereactions is not particularly limited and may be a conventional acidcatalyst. As specific examples of the acid catalyst, there can bementioned inorganic acids such as hydrochloric acid, phosphoric acid andnitric acid; inorganic acid salts such as ammonium chloride and ammoniumnitrate; sulfonic acids such as methanesulfonic acid, p-toluenesulfonicacid and benzenesulfonic acid; sulfonic acid salts such as pyridiniump-toluenesulfonate; acid-type ion exchange resins; and polyvinylpyridine hydrochloride. Of these sulfonic acids and their salts arepreferable, and p-toluenesulfonic acid and its pyridinium salt are morepreferable.

The amount of cis-3-hexen-1-ol is usually in the range of 0.1 to 20moles, preferably 0.5 to 10 moles and more preferably 1 to 5 moles, permole of the acetal compound of formula (2). The amount of the alcohol offormula (5) is usually in the range of 0.05 to 10 moles, preferably 0.1to 5 moles and more preferably 1 to 2.5 moles, per mole of the acetalcompound of formula (4).

The amount of the acid catalyst used for the acetal exchange reactionfor the compound of formula (3) is usually in the range of 0.0001 to 0.1mole, and preferably 0.001 to 0.1 mole, per mole of the acetal compoundof formula (2). The amount of the acid catalyst used for the acetalexchange reaction for the compound of formula (6) also is in the samerange per mole of the acetal compound of formula (4).

The reaction temperature and reaction time in the two acetal exchangereactions are usually 0° to 100° C., preferably 10° to 50° C., andseveral minutes to 10 hours, preferably 10 minutes to 5 hours,respectively. The reaction procedure employed is not particularlylimited, and a procedure wherein the respective reaction ingredients aremixed and stirred is employed. In some cases, an alcohol produced ispreferably distilled off in succession to enhance the rate of reaction.In some cases, the reaction is carried out under a reduced pressurewhich is higher than the vapor pressure of the starting acetal compound(2) or (4) and the vapor pressure of cis-3-hexen-1-ol or alcohol R¹ OH,and is lower than the vapor pressure of the alcohol produced.

After completion of the acetal exchange reaction, thecis-3-hexenal-cis-3-hexenyl acetal compound of formula (1), (3) or (6)can be isolated. As the isolation procedure, there can be mentioned, forexample, a procedure wherein the reaction liquids are washed with anaqueous alkali solution and then the organic phase is distilled. In somecases, it is preferable for preventing or minimizing decompositionoccurring during the distillation that an alkali metal salt of carbonicacid such as calcium carbonate or sodium carbonate, or an amine such astriethanolamine is added.

By the above-mentioned acetal exchange processes, the intendedcis-3-hexenal-cis-3-hexenyl acetal compounds of formula (1), (3) and (6)can be obtained in a high yield and with a high purity.

It is known that part of the compounds of formula (3), for example,cis-3-hexenal-di-cis-3-hexenyl acetal of formula (4), is prepared bycondensing cis-3-hexenal with cis-3-hexenol in the presence of acatalyst and a dehydrating agent (S. Arctander, "perfume and FlavorChemicals", Steffen Arctander's Publications, Las Vegas, Nev. 1969).However, salient amounts of by-products are produced and the intendedcompound cannot be obtained in a high yield and with a high purity.

The fragrance/flavor-imparting effect and fragrance/flavor-retainingeffect of the cis-3-hexenal-cis-3-hexenyl acetal compounds varydepending upon the particular cis-3-hexenal-cis-3-hexenyl acetalcompounds. In general these compounds exhibit a fresch and naturalgreen-note, and retain deep and soft flavors. The green-note of thecompounds delicately vary depending upon the particular kind of R³. Forexample, a cis-3-hexenal-cis-3-hexenyl acetal compound wherein R³ is ahexenyl group with a carbon-carbon unsaturated bond exhibits a lightfloral green-note, and a cis-3-hexenal-cis-3-hexenyl acetal compoundwherein R³ is a a saturated alkyl group such as an ethyl group exhibitsa vegitable green-note. These compounds retain an aromatic flavorspanning from top-note to middle-note, and their formulations exhibitfragrance and are compatible with many perfume materials.

A cis-3-hexenal-cis-3-hexenyl acetal compound wherein R³ is an ethylgroup, i.e., cis-3-hexenal-ethyl-cis-3-hexenyl acetal, has acucumber-like fresh odor, which is a fresh floral green-type fragrancewith a slightly powdery tone. Thus this acetal compound enhances arefreshed natural feeling and is useful as an active ingredient of afragrance-imparting agent. When the cis-3-hexenal-ethyl-cis-3-hexenylacetal is incorporated, floral perfume formulations such as rose,jasmine and lily of the valley are obtained. This acetal compoundimparts a fantastic feeling of high quality to perfumes for soaps,detergents and cosmetics, and enhances retention of these perfumes. Whenthe compound is incorporated in a fruity perfume such as apple,strawberry, pineapple, banana and peach, the sweet, fresh and naturalflavor of the fruity perfume is enhances, and thus, the flavor ofbeverages, ices and confectionary is improved.

A cis-3-hexenal-cis-3-hexenyl acetal compound wherein R³ is a 3-hexenylgroup, i.e., cis-3-hexenal-di-cis-3-hexenyl acetal exhibits a mild andvoluminous floral green fragrance with a slightly powdery tone ofmimosa-like floral perfume. Therefore this acetal compound imparts anatural green tone to various compounds and, further it enhances theretention of fragrance or flavor of the compounds.

When the cis-3-hexenal-cis-3-hexenyl acetal compound of formula (3) isused as a fragrance/flavor-imparting agent or afragrance/flavor-retaining agent in combination with a perfume, theperfume used is not particularly limited and can be chosen fromsynthetic perfumes and natural perfumes. As specific examples of thenatural perfumes, there can be mentioned essential oils such as orangeoil, lemon oil, lime oil, petigrain oil, yuzu oil, neroli oil, bergamotoil, lavender oil, lavandin oil, abies oil, bay oil, rose wood oil,ylang-ylang oil, citronella oil, geranium oil, peppermint oil, spearmintoil, eucalyptus oil, lemongrass oil, patchouli oil, jasmine oil, roseoil, cedar wood oil, vetivert oil, galbanum oil, oak moss oil, pine oil,camphor oil, sandalwood oil, ho leaf oil, turpentine oil, clove oil,clove leaf oil, cassia oil, nutmeg oil, cananga oil and thyme oil; andanimal perfumes such as musk, civet, castoreum and ambergris. Asspecific examples of the synthetic perfumes, there can be mentionedlinalool, linalyl acetate, geraniol, citronellol, aliphatic aldehydeshaving 6 to 12 carbon atoms, phenylethyl alcohol, benzyl acetate,geranyl acetate, geranyl formate, vanillin, nitro musks, galaxolide,tonalid, pentalide, santalex, amyl salicylate, amyl acetate,γ-undecalactone, ethyl methylphenylglycidate and heliotropin. Theseperfumes may be used either alone or as a perfume composition comprisingat least two perfumes.

According to the need, conventional fragrance/flavor-imparting agentsand fragrance/flavor-retaining agents can be used in combination withthe fragrance/flavor-imparting or fragrance/flavor-retaining agent ofthe present invention. Auxiliaries, diluents and other additives such asenzymes, colorants, antioxidants, preservatives, germicides can also beused. Further, nourishing and repairing agents such as crude drugs,vitamins, nutrients, and fats and fatty oils, and modifiers such asbleaching agents, deodorizers and softeners, can also be used incombination with the fragrance/flavor-imparting orfragrance/flavor-retaining agent of the present invention.

The invention will now be specifically described by the followingexamples.

EXAMPLE 1 Synthesis of cis-3-hexenal-ethyl-cis-3-hexenyl acetal(R=ethyl)

A reactor was charged with 34.5 g of cis-3-hexenal-diethyl acetal, 20.0g of cis-3-hexen-1-ol and 4.0 g of pyridinium p-toluenesulfonate. Thereactor was equipped with a reflux condenser, the top part of which isconnected through a cold trap to a vacuuming system. The content wasstirred at 50° C. for 3 hours under a reduced pressure of 10 mmHg.

After completion of the reaction, the reaction mixture was diluted withether and the crystal precipitated was removed by filtration. Thefiltrate was washed with an aqueous sodium carbonate solution and thenwith water. To the organic phase, 1 g of triethanolamine was added andthe mixture was distilled under a reduced pressure of 10 mmHg to removelow-boiling ingredients, and the remainder was distilled under a reducedpressure of 2 mmHg to give 20.5 g (yield 45%) ofcis-3-hexenal-ethyl-cis-3-hexenyl acetal having a boiling point of86°-87° C. at 2 mmHg (the yield is by mole on the basis ofcis-3-hexenal-diethyl acetal).

The spectral data of cis-3-hexenal-cis-hexenyl acetal are shown below.

IR (neat, KBr, cm⁻¹): 3010, 2964, 2933, 2875, 2360, 1657, 1462, 1444,1371, 1344, 1304, 1211, 1120, 1063, 1030, 903, 849, 793, 723

¹ H-NMR (400 MHz, CDCl₃) δ (ppm): 0.89 (t, 6H, J=7.33 Hz), 1.12 (t, 3H,J=6.8 Hz), 1.97 (m, 4H), 2.21-2.32 (m, 4H), 3.33-3.62 (m, 4H), 4.41 (t,1H, J=5.9 Hz), 5.27 (m, 2H), 5.39 (m, 2H)

¹³ C-NMR (400 MHz), CDCl₃) δ (ppm): 14.1, 14.2, 15.2, 20.6, 20.7, 27.9,31.8, 61.1, 65.3, 102.6, 123.1, 124.9, 133.6, 133.9

MS (mass spectrometry) (EI, 70 eV) m/e (%): 181(5), 180(9), 157(21),127(55), 98(17), 83(100), 75(30), 67(14), 55(100), 41(38)

EXAMPLE 2 Synthesis of cis-3-hexenal-di-cis-3-hexenyl acetal(R=cis-3-hexenyl) (1)

A reactor was charged with 43.1 g of cis-3-hexenal-diethyl acetal, 75.1g of cis-3-hexen-1-ol and 5.0 g of pyridinium p-toluenesulfonate. Thereactor was equipped with a reflux condenser, the top part of which isconnected through a cold trap to a vacuuming system. The content wasstirred at 40° C. for 2 hours under a reduced pressure of 10 mmHg.

After completion of the reaction, the reaction mixture was washed withan aqueous sodium carbonate solution and then with water. To the organicphase, 1.5 g of tri-ethanolamine was added and the mixture was distilledunder a reduced pressure of 10 mmHg to remove the predominant part ofthe initial boiling ingredients, and the remainder was distilled under areduced pressure of 1 mmHg to give of cis-3-hexenal-di-cis-3-hexenylacetal having a boiling point of 105°-106° C. at 1 mmHg (the yield is bymole on the basis of cis-3-hexenal-diethyl acetal). Gas chromatographyrevealed that the purity of this compound was 99%.

EXAMPLE 3 Synthesis of cis-3-hexenal-di-cis-3-hexenyl acetal(R=cis-3-hexenyl) (2)

A reactor was charged with 17.3 of cis-3-hexenal-diethyl acetal, 40.1 gof cis-3-hexan-1-ol and 0.40 g of p-toluenesulfonic acid. The reactantswere allowed to react in the same manner as in Example 2 except that thereaction time was changed to 30 minutes. Thuscis-3-hexenal-di-cis-3-hexenyl acetal having a boiling point of125°-128° C. at 2 mmHg was obtained in a yield of 79% (the yield is bymole on the basis of cis-3-hexenal-diethyl acetal). Gas chromatographyrevealed that the purity of this compound was 99%.

The spectral data of cis-3-hexenal-di-cis-3-hexenyl acetal obtained inExamples 2 and 3 are shown below.

IR (neat, KBr, cm⁻¹): 3010, 2964, 2933, 2873, 1655, 1457, 1375, 1346,1304, 1279, 1221, 1120, 1070, 1053, 874, 850, 791, 721

¹ H-NMR (400 MHz, CDCl₃ /TMS) δ (ppm): 14.0, 14.1, 20.5, 20.6, 27.8,31.6, 65.2, 102.6, 123.1, 124.9, 133.4, 133.7

MS (EI, 70 eV) m/e (%): 181(7), 180(41), 157(6), 127(15), 98(54),83(78), 75(6), 67(12), 55(100), 41(55)

EXAMPLES 4-6 Synthesis of:

(1) cis-3-hexenal-methyl-cis-3-hexenyl acetal (R=methyl),

(2) cis-3-hexenal-propyl-cis-3-hexenyl acetal (R=n-propyl), and

(3) cis-3-hexenal-butyl-cis-3-hexenyl acetal (R=n-butyl).

A flask was charged with 98.15 g (0.35 mole) ofcis-3-hexenal-di-cis-3-hexenyl acetal, 0.35 mole of methanol (Example4), n-propanol (Example 5) or n-butanol (Example 6), and 0.74 g ofp-toluenesulfonic acid monohydrate, and the content was stirred at roomtemperature for 1 hour by a magnetic stirrer to effect an acetalexchange reaction. The reaction mixture was washed with 50 ml of a 5%aqueous sodium carbonate solution, and the separated organic phase wassubjected to fractional distillation under a reduced pressure of 2 mmHgto give the above-mentioned acetal compounds (1), (2) or (3).

The boiling point and yield of the acetal compounds (1), (2) and (3)were as follows. (the yield is by mole on the basis of the chargedcis-3-hexenal-di-cis-3-hexenyl acetal)

    ______________________________________                                                   Acetal      Boiling point                                                                           Yield                                        Example No.                                                                              compound    (°C./mmHg)                                                                       (mole %)                                     ______________________________________                                        4          (1) R = methyl                                                                            78-81/2   38.1                                         5          (2) R = n-propyl                                                                          100-103/2 38.9                                         6          (3) R = n-butyl                                                                           113-117/2 41.0                                         ______________________________________                                    

The spectral data of the acetal compounds (1), (2) and (3) are shownbelow.

(1) Cis-3-hexenal-methyl-cis-3-hexenyl acetal

IR (neat, KBr, cm⁻¹): 3010, 2964, 2933, 2875, 2829, 1655, 1464, 1405,1375, 1360, 1348, 1306, 1281, 1225, 1190, 1120, 1068, 968, 918, 870,847, 827, 793, 723

¹ H-NMR (400 MHz), CDCl₃ /TMS) δ (ppm): 0.97(6H), 2.06 (4H), 2.30-2.40(m, 4H), 3.33 (s, 3H), 3.41-3.48 (m, H), 3.55-3.62 (m, H), 4.41 (t, 1H,J=5.62 Hz), 5.31-5.39 (m, 2H), 5.44-5.53 (m, 2H)

¹³ C-NMR (400 MHz), CDCl₃ /TMS) δ (ppm): 14.1, 14.2, 20.7, 20.8, 28.0,31.4, 52.8, 65.6, 103.6, 123.0, 125.0, 133.7, 134.1

MS (EI, 70 eV) m/e (%): 212 (M⁺, 0.05), 181(1.5), 180(1), 143(11),113(31), 97(2), 83(100), 81(13), 71(12), 61(8), 55(62), 45(5), 41(22)

(2) Cis-3-hexenal-propyl-cis-3-hexenyl acetal

IR (neat, KBr, cm⁻¹): 3010, 2964, 2935, 2875, 1655, 1464, 1404, 1375,1350, 1304, 1281, 1219, 1120, 1068, 1036, 993, 970, 908, 874, 793, 725

¹ H-NMR (400 MHz, CDCl₃ /TMS), δ (ppm): 0.91-0.99 (m, 9H), 1.59 (m, 2H),2.06 (m, 4H), 2.29-2.41 (m, 4H), 3.37-3.48 (m, 2H), 3.52-3.62 (m, 2H),4.49 (t, 1H, J=5.86 Hz), 5.32-5.39 (m, 2H), 5.43-5.52 (m, 2H)

¹³ C-NMR (400 MHz, CDCl₃ /TMS) δ (ppm): 10.8, 14.2, 14.3, 20.7, 20.8,23.1, 28.0, 31.9, 65.3, 67.5, 102.8, 123.3, 125.0, 133.6, 133.9

MS (EI, 70 eV) m/e (%): 240 (M⁺, 0.1), 181(3), 180(1), 171(11), 141(28),99(5), 89(17), 83(100), 81(19), 67(8), 55(58), 43(21), 41(23)

(3) Cis-3-hexenal-butyl-cis-3-hexenyl acetal

IR (neat, KBr, cm⁻¹): 3010, 2962, 2933, 2873, 1655, 1464, 1435, 1404,1379, 1346, 1306, 1279, 1217, 1119, 1070, 1045, 970, 891, 872, 849, 795,725

¹ H-NMR (400 MHz), CDCl₃ /TMS), δ (ppm): 0.90-0.99 (m, 9H), 1.33-1.44(m, 2H), 1.51-1.60 (m, 2H), 2.02-2.10 (m, 4H), 2.29-2.40 (m, 4H),3.40-3.48 (m, 2H), 3.55-3.62 (m, 2H), 4.48 (t, 1H, J=5.86 Hz), 5.32-5.39(m, 2H), 5.33-5.52 (m, 2H)

¹³ C-NMR (400 MHz, CDCl₃ /TMS) δ (ppm): 13.9, 14.2, 14.3, 19.5, 20.7,20.8, 28.0, 31.8, 32.0, 65.3, 65.6, 102.8, 123.3, 125.0, 133.6, 133.9

MS (EI, 70 eV) m/e (%): 254 (M⁺, 0.16), 185(11), 181(3), 180(2),155(25), 137(2), 103(14), 83(100), 81(19), 67(8), 57(27), 55(57), 41(24)

EXAMPLE 7 Perfume composition (1) containingcis-3-hexenal-ethyl-cis-3-hexenyl acetal

The ingredients shown in Table 1 were mixed together to prepare a rosadamascena (rose damask)-tone floral base fragrant composition. To 100parts by weight of this rosa damascena (rose damask)-tone floral basefragrant composition, 1 part by weight ofcis-3-hexenal-ethyl-cis-3-hexenyl acetal was incorporated to prepare aperfume composition. The top note was of freshness with a natural greentone, and was of broad diffusibility and good retainability. The naturaltone of the perfume was enhanced.

                  TABLE 1                                                         ______________________________________                                        Ingredient    Amount (parts by weight)                                        ______________________________________                                        Citral        0.5                                                             C9 aldehyde   0.5                                                             Damascenone   1.0                                                             Rose oxide    5.0                                                             Phenylethyl acetate                                                                         5.0                                                             Geranyl acetate                                                                             8.0                                                             Terpineol     10.0                                                            Farnesol      10.0                                                            Phenylethyl alcohol                                                                         15.0                                                            Geranium oil  30.0                                                            Nerol         90.0                                                            Geraniol      160.0                                                           Citronellol   320.0                                                           Carryophyllene                                                                              5.0                                                             Eugenol       6.0                                                             Sandalwood oil                                                                              10.0                                                            Methyl eugenol                                                                              24.0                                                            2-Phenoxyethanol                                                                            300.0                                                           Total         1000.0                                                          ______________________________________                                    

EXAMPLE 8 Perfume composition (2) containingcis-3-hexenal-ethyl-cis-3-hexenyl acetal (R=ethyl)

The ingredients shown in Table 2 were mixed together to prepare a whitepeach fruit fragrant composition. To 100 parts by weight of this whitepeach fruit fragrant composition, 0.65 part by weight ofcis-3-hexenal-ethyl-cis-3-hexenyl acetal was incorporated to prepare aperfume composition. The perfume exhibited natural tone flavor with anenhanced fresh sweet taste of white peach.

                  TABLE 2                                                         ______________________________________                                        Ingredient      Amount (parts by weight)                                      ______________________________________                                        Hexyl acetate   0.9                                                           Benzaldehyde    1.2                                                           Benzyl alcohol  1.2                                                           Cis-3-hexenyl acetate                                                                         4.0                                                           Cis-3-hexenol   5.0                                                           Hexanol         15.0                                                          Trans-2-hexenyl acetate                                                                       15.0                                                          Rinalool        18.0                                                          γ-Tridecalactone                                                                        0.5                                                           γ-Nonalactone                                                                           0.5                                                           γ-Heptalactone                                                                          1.0                                                           δ-Octalactone                                                                           1.2                                                           γ-Octalactone                                                                           5.0                                                           Jasmine lactone 5.0                                                           γ-Dodecalactone                                                                         14.0                                                          δ-Decalactone                                                                           22.0                                                          γ-Hexalactone                                                                           27.0                                                          γ-Decalactone                                                                           85.0                                                          Triacetin       778.5                                                         Total           1000.0                                                        ______________________________________                                    

EXAMPLE 9 Perfume compositions (3) and (4) containingcis-3-hexenal-di-cis-3-hexenyl acetal (R=hexenyl)

The ingredients shown in Table 3 were mixed together to prepare twokinds of fruity sweet green base perfume compositions (A) and (B). Thecomposition (B) contained cis-3-hexenal-di-cis-3-hexenyl acetal, but thecomposition (A) did not contain the acetal compound.

The ingredients shown in Table 4 were mixed together to prepare twokinds of fresh spicy green base perfume compositions (A) and (B). Thecomposition (B) contained the acetal compound, but the composition (A)did not contain the acetal compound.

The compositions (B) containing the acetal compound exhibited milder andmore natural fragrances than those of the compositions (A).

                  TABLE 3                                                         ______________________________________                                        Fruity Green Base                                                                              Composition A                                                                            Composition B                                     Ingredient       (weight parts)                                                                           (weight parts)                                    ______________________________________                                        Citral           0.2        0.2                                               Cis-3-hexenyl anthranilate                                                                     0.3        0.3                                               Hexyl n-butyrate 0.4        0.4                                               Cis-3-hexenyl n-butyrate                                                                       0.5        0.5                                               Raspberry ketone (1%)                                                                          0.6        0.6                                               Zeppin (methyl jasmonate)                                                                      0.8        0.8                                               γ-Decalactone                                                                            1.0        1.0                                               Extra green (cis-3-hexenol)                                                                    1.2        1.2                                               Methyl benzoate  2.0        2.0                                               γ-Nonalactone                                                                            3.0        3.0                                               Cepionate        6.0        6.0                                               (methyl dihydrojasmonate)                                                     Cis-3-hexyl benzoate                                                                           6.0        6.0                                               Cis-3-hexenal-di-cis-3-                                                                        --         6.0                                               hexenyl acetal                                                                Benzyl acetate   6.0        6.0                                               Benzyl benzoate  8.0        8.0                                               Linalool         14.0       14.0                                              γ-Undecalactone                                                                          24.0       24.0                                              Ethyl maltol (1%)                                                                              2.0        2.0                                               Vanillin (10%)   4.0        4.0                                               Triacetin        20.0       20.0                                              Total            100.0      100.0                                             ______________________________________                                    

                  TABLE 4                                                         ______________________________________                                        Fresh Spicy Green Base                                                                        Composition A                                                                            Composition B                                      Ingredient      (weight parts)                                                                           (weight parts)                                     ______________________________________                                        Verbena oil     2.0        2.0                                                C10-aldehyde    3.0        3.0                                                Herional        3.0        3.0                                                Basil oil       3.0        3.0                                                Lemon oil       4.0        4.0                                                Taragon oil     5.0        5.0                                                Grape fruit oil 10.0       10.0                                               Cis-3-hexenal-di-cis-3-                                                                       --         10.0                                               hexenyl acetal                                                                Styralyl acetate                                                                              15.0       15.0                                               Lavender oil    20.0       20.0                                               Bergamot oil (non-                                                                            25.0       25.0                                               photosensitive non-toxic)                                                     2-Phenoxyethanol                                                                              10.0       --                                                 Total           100.0      100.0                                              ______________________________________                                    

EXAMPLE 10 Perfume compositions (5) and (6) containingcis-3-hexenal-di-cis-3-hexenyl acetal (R=3hexenyl)

The ingredients shown in Table 5 were mixed together to prepare twokinds of blue hyacinth base perfume compositions (A) and (B). Thecomposition (B) contained cis-3-hexenal-di-cis-3-hexenyl acetal, but thecomposition (A) did not contain the acetal compound.

The ingredients shown in Table 6 were mixed together to prepare twokinds of mimosa base perfume compositions (A) and (B). The composition(B) contained the acetal compound, but the composition (A) did notcontain the acetal compound.

The compositions (B) containing the acetal compound exhibited softer andmore voluminous and delightful floral fragrances than those of thecompositions (A).

                  TABLE 5                                                         ______________________________________                                        Blue Hyacinth Base                                                                            Composition A                                                                            Composition B                                      Ingredient      (weight parts)                                                                           (weight parts)                                     ______________________________________                                        Sweet birch oil 0.1        0.1                                                3-Phenylpropyl acetate                                                                        0.1        0.1                                                Cinnamyl nitrate                                                                              0.2        0.2                                                Cis-3-hexyl anthranilate                                                                      0.3        0.3                                                Cinnamyl benzoate                                                                             0.4        0.4                                                Ylang ylang absolute                                                                          1.0        1.0                                                Cinnamyl acetate                                                                              1.4        1.4                                                Cis-3-hexenal-di-cis-3-                                                                       --         1.5                                                hexenyl acetal                                                                3-Phenylpropanol                                                                              1.5        1.5                                                Phenylethyl alcohol                                                                           2.0        2.0                                                Methyl eugenol  2.0        2.0                                                Phenylethyl benzoate                                                                          3.0        3.0                                                Benzyl alcohol  3.0        3.0                                                2-Phenoxyethanol                                                                              6.0        4.5                                                3-Methoxyphenylethanol                                                                        10.0       10.0                                               Benzyl acetate  15.0       15.0                                               Benzyl benzoate 20.0       20.0                                               Cinnamyl alcohol                                                                              30.0       30.0                                               Methyl palmitate                                                                              2.0        2.0                                                Methyl anisate  2.0        2.0                                                Total           100.0      100.0                                              ______________________________________                                    

                  TABLE 6                                                         ______________________________________                                        Mimosa Base                                                                                    Composition A                                                                            Composition B                                     Ingredient       (weight parts)                                                                           (weight parts)                                    ______________________________________                                        Cis-3-hexyl acetate                                                                            0.1        0.1                                               p-Methylacetophenone                                                                           0.2        0.2                                               Cis-3-hexenyl benzoate                                                                         0.3        0.3                                               C9-aldehyde      0.5        0.5                                               C10-aldehyde     0.5        0.5                                               Bergamot oil     0.6        0.6                                               Cinnamyl alcohol 0.6        0.6                                               Cis-3-hexenal-di-cis-3-                                                                        --         1.0                                               hexenyl acetal                                                                Anisaldehyde     1.0        1.0                                               Methyl isoeugenol                                                                              1.0        1.0                                               Ylang ylang absolute                                                                           1.0        1.0                                               Ethyl benzoate   1.5        1.5                                               Benzyl alcohol   2.0        2.0                                               Helional         3.0        3.0                                               Terpineol        3.0        3.0                                               Cepionate        4.0        4.0                                               (methyl dihydrojasmonate)                                                     Benzyl benzoate  6.0        6.0                                               Lyral            12.0       12.0                                              Benzyl salycylate                                                                              28.0       28.0                                              Eugenol          0.5        0.5                                               Guaiac oil       1.0        1.0                                               Ionone-alpha     1.0        1.0                                               Ethyl linolate   27.0       26.0                                              Heliotropin      1.2        1.2                                               Methyl anisate   3.0        3.0                                               Total            100.0      100.0                                             ______________________________________                                    

EXAMPLE 11 Perfume compositions (7) and (8) containingcis-3-hexenal-di-cis-3-hexenyl acetal (R=3-hexenyl)

Floral base compositions other than green floral bases were prepared.Namely, the ingredients shown in Table 7 were mixed together to preparetwo kinds of rose de mai (rose of May) base perfume compositions (A) and(B). The composition (B) contained cis-3-hexenal-di-cis-3-hexenylacetal, but the composition (A) did not contain the acetal compound. Theingredients shown in Table 8 were mixed together to prepare two kinds ofpurple lilac base perfume compositions (A) and (B). The composition (B)contained the acetal compound, but the composition (A) did not containthe acetal compound. The top note of the compositions (B) containing theacetal compound was of soft, fresh and elegant floral tone.

                  TABLE 7                                                         ______________________________________                                        Rose-De-Mai Base                                                                              Composition A                                                                            Composition B                                      Ingredient      (weight parts)                                                                           (weight parts)                                     ______________________________________                                        Rose oxide L    0.2        0.2                                                Phenylacetoaldehyde                                                                           0.2        0.2                                                Citral          0.3        0.3                                                Damascenone     0.4        0.4                                                Cis-3-hexenal-di-cis-3-                                                                       --         0.5                                                hexenyl acetal                                                                Rhodinyl acetate                                                                              0.6        0.6                                                Terpenol alpha  0.8        0.8                                                Benzyl alcohol  1.0        1.0                                                Nerol           2.0        2.0                                                Phenylethyl acetate                                                                           3.0        3.0                                                Rhodinol        15.0       15.0                                               Phenylethyl alcohol                                                                           70.0       70.0                                               Guail acetate   1.0        1.0                                                Clove oil       1.0        1.0                                                Methyleugenol   2.0        2.0                                                2-Phenoxyethanol                                                                              2.5        2.0                                                Total           100.0      100.0                                              ______________________________________                                    

                  TABLE 8                                                         ______________________________________                                        Purple Lilac                                                                                   Composition A                                                                            Composition B                                     Ingredient       (weight parts)                                                                           (weight parts)                                    ______________________________________                                        Cis-3-hexenyl anthranilate                                                                     0.1        0.1                                               Cis-3-hexenyl acetate                                                                          0.1        0.1                                               Extra green (cis-3-hexenol)                                                                    0.3        0.3                                               Zeppin (methyl jasmonate)                                                                      0.3        0.3                                               Tetrahydorgeraniol                                                                             0.5        0.5                                               Cinnamic acetate 0.5        0.5                                               Cis-3-hexenal-di-cis-3-                                                                        --         1.0                                               hexenyl acetal                                                                Linalool         1.0        1.0                                               Ylang ylang absolute                                                                           1.0        1.0                                               Phenylacetoaldehyde                                                                            2.0        2.0                                               glycerin acetal                                                               3-Phenylpropanol 2.0        2.0                                               Styrax resinoid  3.0        3.0                                               Anisaldehyde     3.0        3.0                                               Phenylethyldimethylcarbinol                                                                    4.0        4.0                                               Cinnamyl alcohol 4.0        4.0                                               Terpineol alpha  6.0        6.0                                               2-Phenoxyethanol 10.0       9.0                                               Benzyl alcohol   10.0       10.0                                              Phenylethyl alcohol                                                                            20.0       20.0                                              Lilial           30.0       30.0                                              Indole           0.2        0.2                                               Dimethylhydroquinone                                                                           2.0        2.0                                               Total            100.0      100.0                                             ______________________________________                                    

Industrial Applicability

The cis-3-hexenal-cis-3-hexenyl acetal compounds represented by theabove-mentioned formulae (1), (2) and (3) are useful as afragrance/flavor-imparting agent and a fragrance/flavor-retaining agent,and can be incorporated in the following products.

Food and drink, for example, beverages such as fruit juices, fruitwines, dairy beverages and carbonated beverages; ices such as icecreams, sherbets and ice-candies; confectionery such as Japanese andwestern sweets and cakes; luxuries such as jams, chewing gums, bread,coffee, cocoa chocolate, black tea and Japanese tea; soup such as soupand Japanese soup; flavorings, instant food and drink, snacks; cosmeticssuch as perfumes, Eau de Cologne, lotions, shampoos, hair cosmetic basesfor hair cream and pomade, cosmetic bases; hygienic detergents such aswashing detergents, sterilizing detergents, deodorizing detergents, androom aromatics; medical and hygienic supplies such as toothpastes,tissues and toilet paper; medicines and medical supplies such astablets, granules, ointments, powders and others.

We claim:
 1. A cis-3-hexenal-cis-3-hexenyl acetal compound representedby the following formula (1): ##STR8## wherein R represents an alkylgroup, having 1 to 20 carbon atoms.
 2. The acetal compound as claimed inclaim 1, wherein R is an alkyl group having 1 to 10 carbon atoms andhaving no substituent.
 3. The acetal compound as claimed in claim 1,wherein R is an alkyl group selected from methyl, ethyl, propyl andbutyl groups.
 4. A process for preparing a cis-3-hexenal-cis-3-hexenylacetal compound represented by the following formula (3): ##STR9##wherein R³ represents a hydrocarbon group, which comprises conducting anacetal exchange reaction at a temperature of 0° to 100° C. in thepresence of an acid catalyst between an acetal compound represented bythe following formula (2): ##STR10## wherein R¹ and R² independentlyrepresent a hydrocarbon group except for a 3-hexenyl group, and 0.1 to20 moles, per mole of acetal compound of formula (2), ofcis-3-hexen-1-ol.
 5. The process as claimed in claim 4, wherein R¹ andR² are independently selected from an alkyl group having 1 to 20 carbonatoms, an alkenyl group having 2 to 20 carbon atoms, except for3-hexenyl group, and an alkynyl group having 2 to 20 carbon atoms. 6.The process as claimed in claim 4, wherein R¹ and R² are independentlyselected from an alkyl group having 1 to 15 carbon atoms and having nosubstituent, an alkenyl group having 2 to 15 carbon atoms, except for3-hexenyl group, and having no substituent, and an alkynyl group having2 to 15 carbon atoms and having no substituent.
 7. The process asclaimed in claim 4, wherein R¹ and R² are independently selected from analkyl group having 1 to 8 carbon atoms and having no substituent, analkenyl group having 2 to 8 carbon atoms and having no substituent,except for 3-hexenyl group, and an alkynyl group having 2 to 8 carbonatoms and having no substituent.
 8. The process as claimed in claim 4,wherein R¹ and R² are independently selected from methyl, ethyl, propyland butyl groups.
 9. The process as claimed in claim 4 wherein R³ isselected from an alkyl group having 1 to 20 carbon atoms, an alkenylgroup having 2 to 20 carbon atoms, and an alkynyl group having 2 to 20carbon atoms.
 10. The process as claimed in claim 4 wherein R³ isselected from an alkyl group having 1 to 15 carbon atoms and having nosubstituent, an alkenyl group having 2 to 15 carbon atoms and having nosubstituent, and an alkynyl group having 2 to 15 carbon atoms and havingno substituent.
 11. The process as claimed in claim 4 wherein R³ isselected from an alkyl group having 1 to 8 carbon atoms and having nosubstituent, an alkenyl group having 2 to 8 carbon atoms and having nosubstituent, and an alkynyl group having 2 to 8 carbon atoms and havingno substituent.
 12. The process as claimed in claim 4 wherein R³ is analkyl group selected from methyl, ethyl, propyl and butyl groups, or a3-hexenyl group.
 13. The process as claimed in claim 4 wherein the acidcatalyst is p-toluenesulfonic acid or a salt thereof.
 14. The process asclaimed in claim 4 wherein the amount of cis-3-hexen-1-ol is in therange of 0.5 to 10 moles per mole of the acetal compound of formula (2).15. A process for preparing a cis-3-hexenal-cis-3-hexenyl acetalcompound represented by the following formula (6): ##STR11## wherein R¹is a hydrocarbon group, except for 3-hexenyl group, which comprisesconducting an acetal exchange reaction at a temperature of 0° to 100° C.in the presence of an acid catalyst betweencis-3-hexenal-di-cis-3-hexenyl acetal represented by the followingformula (4): ##STR12## and 0.05 to 10 moles, per mole of the acetalcompound of formula (4), of an alcohol represented by the followingformula (5):

    R.sup.1 OH                                                 (5)

wherein R¹ is the same as defined above for formula (6).
 16. The processas claimed in claim 15, wherein R¹ is selected from an alkyl grouphaving 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbonatoms, except for 3-hexenyl group, and an alkynyl group having 2 to 20carbon atoms.
 17. The process as claimed in claim 15, wherein R¹ isselected from an alkyl group having 1 to 15 carbon atoms and having nosubstituent, an alkenyl group having 2 to 15 carbon atoms, except for3-hexenyl group, and having no substituent, and an alkynyl group having2 to 15 carbon atoms.
 18. The process as claimed in claim 15, wherein R¹is selected from an alkyl group having 1 to 8 carbon atoms and having nosubstituent, an alkenyl group having 2 to 8 carbon atoms, except for3-hexenyl group, and having no substituent, and an alkynyl group having2 to 8 carbon atoms.
 19. The process as claimed in claim 15, wherein R¹is selected from methyl, ethyl, propyl and butyl groups.
 20. The processas claimed in any of claims 15 to 19, wherein the acid catalyst isp-toluenesulfonic acid or a salt thereof.
 21. The process as claimed inclaim 15 wherein the amount of alcohol of formula (5) is in the range of0.1 to 5 moles per mole of the acetal compound of formula (4).
 22. Afragrance- or flavor-imparting or fragrance- or flavor-retaining agentcomprising as an active ingredient a cis-3-hexenal-cis-3-hexenyl acetalcompound represented by the following formula (3): ##STR13## wherein R³represents a hydrocarbon group.
 23. The fragrance- or flavor-impartingor fragrance- or flavor-retaining agent as claimed in claim 22, whereinR³ is selected from an alkyl group having 1 to 20 carbon atoms, analkenyl group having 2 to 20 carbon atoms, and an alkynyl group having 2to 20 carbon atoms.
 24. The fragrance- or flavor-imparting or fragrance-or flavor-retaining agent as claimed in claim 22, wherein R³ is selectedfrom an alkyl group having 1 to 15 carbon atoms and having nosubstituent, an alkenyl group having 2 to 15 carbon atoms and having nosubstituent, and an alkynyl group having 2 to 15 carbon atoms and havingno substituent.
 25. The fragrance- or flavor-imparting or fragrance- orflavor-retaining agent as claimed in claim 22, wherein R³ is selectedfrom an alkyl group having 1 to 8 carbon atoms and having nosubstituent, an alkenyl group having 2 to 8 carbon atoms and having nosubstituent, and an alkynyl group having 2 to 8 carbon atoms and havingno substituent.
 26. The fragrance- or flavor-imparting or fragrance- orflavor-retaining agent as claimed in claim 22, wherein R³ is an alkylgroup selected from methyl, ethyl, propyl and butyl groups, or a3-hexenyl group.
 27. A perfume composition comprising as an activeperfuming ingredient or perfume-retaining ingredient acis-3-hexenal-cis-3-hexenyl acetal compound represented by the followingformula (3): ##STR14## wherein R³ represents a hydrocarbon group. 28.The perfume composition as claimed in claim 27, wherein R³ is selectedfrom an alkyl group having 1 to 20 carbon atoms, an alkenyl group having2 to 20 carbon atoms, and an alkynyl group having 2 to 20 carbon atoms.29. The perfume composition as claimed in claim 27, wherein R³ isselected from an alkyl group having 1 to 15 carbon atoms and having nosubstituent, an alkenyl group having 2 to 15 carbon atoms and having nosubstituent, and an alkynyl group having 2 to 15 carbon atoms and havingno substituent.
 30. The perfume composition as claimed in claim 27,wherein R³ is selected from an alkyl group having 1 to 8 carbon atomsand having no substituent, an alkenyl group having 2 to 8 carbon atomsand having no substituent, and an alkynyl group having 2 to 8 carbonatoms and having no substituent.
 31. The perfume composition as claimedin claim 27, wherein R³ is an alkyl group selected from methyl, ethyl,propyl and butyl groups, or a 3-hexenyl group.